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Omar,
Here is how you can estimate the size
of a quadrant.
When your eye is near the back sight mirror
(you see a round hole in the frame on your picture,
it roughly indicates where your eye should be),
and you hold the quadrant vertically,
the index mirror should be well above your head.
So that you could see the horizon behind you
unobscured by your head.
The height from MY eye to the top of my head is approx.
6 inches, from which I conclude (by rough measurement
with a rule on my computer screen) that the arc radius
of your quadrant is about 20-22 inches.

Alex.

On Fri, 19 Nov 2004, Omar Reis wrote:

> Hello,
>
> I'm trying to build an octant similar do Bowditch's.
>
> I found a beautiful image of it on the following address:
>
> www.nathanielbowditch.org/images/sextantb.jpg
>
> I wonder if anyone knows more details about this instrument:
>
> 1) Scale radius
>
> 2) Number of minutes in the vernier ( i.e. tick divisions per degree )
>
> Regards
> Omar
>

   

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